Reese Witherspoon-ish, bright and hopeful, is the heroine of “The 100,” a new CW drama based on a post-apocalyptic young adult novel by Kass Morgan. You’ve heard of that genre, right? The show, premiering Wednesday night at 9, is both “The Hunger Games”-ish and “Lord of the Flies”-ish. And maybe a little “Lost”-ish, too, not least of all because Henry Ian Cusick — he was Desmond on “Lost” — is part of the cast.

Unlike on “Lost,” the Scottish actor’s accent on “The 100” is — to put it kindly — American-ish.

The antagonist to the blond Reese-ish ingenue Clarke (Eliza Taylor) is Neve Campbell-ish, a dark beauty named Octavia (Marie Avgeropoulos) who has mischief playing in her eyes. The two have the same taste in boys, which is where the Johnny Depp-ish maverick Finn (Thomas McDonell) comes in.

But first: The construct is that 97 years ago, life on Earth was nearly destroyed by a nuclear Armageddon. The only human survivors were the 400 inhabitants of 12 international space stations, all of whom have since joined to form a giant city-in-orbit known as the Ark. Now holding 4,000 residents, the Ark is running out of resources, and 100 juvenile delinquents and young political prisoners have been sent to Earth to find out if it has become habitable. Which it is — ish, since the deer grazing in the newly grown forests have two heads.

After landing, the teenagers begin to battle among themselves. The Reese-ish, Neve-ish, Depp-ish, and a few other characters form a search party and set out to find a mountain bunker filled with supplies. “There’s a radioactive forest between us and our next meal,” Clarke exclaims. As they journey forth, they frolic and flirt while the writers strain to establish opportunities for tender kisses. Meanwhile, those kids who’ve remained near the landing begin to party with abandon, and those who were working class on the Ark turn on those whose parents were in positions of power, notably Wells (Eli Goree), the son of the Chancellor (Isaiah Washington).

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All these young people are essentially canaries in a coal mine, and they know it. They have been deemed expendable. That doesn’t inspire their loyalty to the Ark leaders up high in the sky, so they quickly throw a few communication curveballs at the mother ship, leaving the Chancellor and Cusick’s cold-hearted second-in-command in an unhappy cloud of unknowing.

Obviously “The 100” is built on a too-familiar premise, one that series such as “Terra Nova” and “Revolution” have also mined. We get it, we’re all concerned about the future of the planet and its occupants. Our attraction to Apocalypse TV runs deep, as our culture plays out different futuristic possibilities. That’s still no reason to clone material, nor is it a reason to deliver characters who are little more than stereotypes — stereotypes already overly exploited on the CW.

Clarke is played with a shallow sweetness by Taylor. If she is going to essentially carry the moral weight of the show on her shoulders, she’s going to need to cultivate a more complex persona. Likewise, if McDonell is going to be a compelling romantic lead as Finn, he needs a more definitive presence. Right now, he’s vague and too recessive. They don’t make the future of our species seem very promising.

If you don’t think too much about details and leaps in logic, “The 100” moves forward swiftly. But the characters seem stuck in place, with one foot placed firmly in central casting. They’re bland, no ish about it.